1. Field of the Invention
This invention relates to an indium source reagent composition having utility for incorporation of indium in a microelectronic device structure, e.g., as an indium-containing film on a device substrate by bubbler or liquid delivery MOCVD techniques, or as a dopant species incorporated in a device substrate by ion implantation techniques. The invention also relates to such semiconductor fabrication techniques for using the indium source reagent of the invention, as well as to microelectronic device structures incorporating indium by use of such source reagent and techniques.
2. Description of the Related Art
In the field of semiconductor manufacturing, indium is a material of considerable current and future technological importance.
With the emergence and proliferation of copper as a preferred material in metallization for formation of conductor transmission lines of integrated circuitry devices, copper-indium (Cu/In) alloys are of great interest for improving the long-term performance, electro-migration resistance and reliability of copper-based interconnects. Indium-containing III-V semiconductor materials also will play an increasingly important role in the development of electronic and optoelectronic devices.
The most commonly used In precursors for the deposition of In-based materials are trialkylindium, such as trimethylindium and triethylindium. For the chemical vapor deposition (CVD) of Cu/In alloys, such conventional In precursors are not compatible with currently used Cu precursors, when multiple source precursors (for In and Cu) are introduced. In addition, the conventional In precursors are extremely sensitive to air, oxygen and moisture, leading to vigorous exothermic reactions, fire and explosions when exposed to such ambient atmospheric constituents.
Indium also is of great current interest in the microelectronics field as a potential dopant species for the formation of doped shallow junctions in integrated circuitry devices, since shallow device junctions enable high performance devices to be fabricated at lower switching voltages than are required for junctions of greater depth. Further, in relation to other dopant species that may be employed for forming doped junction structures by conventional ion implantation techniques, indium has the significant advantage that its size and mass allow lower implant energies to be used, provided that useful beam currents of In ions can be obtained.
The beam current is a critical aspect of the ion implantation operation as practiced in conventional ion implanter systems, and is strongly precursor material-dependent in character. Specifically, the vaporization and delivery of the precursor for ionization and ion beam transport of the implant species typically requires a material of suitable volatility and transport characteristics, but volatile liquids and solids when used as precursors also create a potential risk of introduction of reactive species that are susceptible to side-reactions and also create the potential for contamination of the substrate and disruption of the desired device characteristics.
Given these circumstances, there is a compelling need in the art for new In precursors suitable for deposition of In-based materials or ion implantation of In in semiconductor device structures.